1. Field of the Invention
The present invention relates to an apparatus for reducing disturbances induced in a signal measurement or recording, in particular, but not exclusively, by movement of the electrodes or changes in the pressure applied to the electrodes.
2. Brief Description of the Prior Art
Oesophageal recording of diaphragm electromyogram (EMG) has traditionally been problematic due to the low amplitude of the EMG signal relative to the artifactual disturbances such as, in particular, the so-called electrode motion artifacts. At high gain settings, large electrode motion artifacts lead to saturation of the output of the preamplifier, thereby causing a temporary loss of the EMG signal. This problem of the prior art makes EMG recording very difficult during dynamic manoeuvres, such as for example rapid shallow breathing or panting.
A first object of the present invention is to provide a technology capable of reducing disturbances induced in a measurement or recording by:
movements of detecting electrodes;
changes in the pressure applied to these electrodes; or
other mechanical influence on the electrodes, generally referred to as motion artifacts.
Another object of the present invention is to reduce the amplitude of motion artifacts relative to the amplitude of the EMG signal to thereby reduce the possibility for saturation of the preamplifier.
A third object of the present invention is to overcome the problems of the prior art related to low signal-to-artifact ratio.
A further object of the present invention is to improve bipolar electrode measurements of diaphragm electromyogram (EMG).
In a preferred embodiment of the invention, there is provided a measurement apparatus for detecting an electrical signal produced by a muscle while reducing signal disturbances caused by motion artifacts, the measurement apparatus comprises:
a) a probe;
b) at least one electrode mounted on said probe; and
c) a disturbance reducing interface attached to said probe and covering said at least one electrode, the interface being ion permeable and segregating said at least one electrode from the muscle.
The objects, advantages and other features of the present invention will become more apparent upon reading of the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.